STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Beam 1.0 501B A23B vs Claude Sonnet 5.5

Claude Sonnet 5.5 leads Beam 1.0 501B A23B by 38.3 points on StealthMark, 70.2 to 31.9. It leads on all 9 benchmarks. Claude Sonnet 5.5 scores higher on Newton's Mirror, with its largest category advantage in reflections.

See the difference ↘
All results ↗
All results ↗

Overall StealthMark

31.9/100Overall rank 42/53
70.2/100Overall rank 3/53

General Intelligence

30.9/100
67.0/100

Visual Intelligence

33.8/100
76.1/100

Reasoning efficiency

On every task, result quality and reasoning tokens are each compared with all measured models and weighed equally. Each dot is one model.

Single-step reasoning Result quality weighed against reasoning tokens on a single problem

Multi-step reasoning Result quality weighed against reasoning tokens across connected steps, as in agentic workflows

  • Claude Sonnet 5.5

Open or local

Open modelApache 2.0

BENCHMARK BY BENCHMARK

Where each model leads

  • Beam 1.0 501B A23B
  • Claude Sonnet 5.5
  • Other models
  • Median

DATASHEET

Specs and pricing

Beam 1.0 501B A23B is 10× cheaper per output token and runs 3.9× faster in our speed test. Claude Sonnet 5.5 scores higher on StealthMark. Both take about 1M tokens of context.

  • Beam 1.0 501B A23B
  • Claude Sonnet 5.5
  • Other models
  • Median
PricePer 1M output tokens, input below
Beam 1.0 501B A23B: $110× cheaper$0.25 inputClaude Sonnet 5.5: $10$2 input
Context windowTokens per request, max output below
Beam 1.0 501B A23B: 1MTied128K max outputClaude Sonnet 5.5: 1MTied128K max output
Output speedTokens per second, our measurement
Beam 1.0 501B A23B: 9723.9× fastertokens/sClaude Sonnet 5.5: 249tokens/s
SizeTotal and active parameters
Beam 1.0 501B A23B: 501B23.4B activeClaude Sonnet 5.5: Not disclosed
Developer
Reflection AIAnthropic
Released
16 Oct 202628 Sep 2026
Origin
United StatesBoth
Input → output
Text → textText, image → text
Architecture
Sparse mixture-of-experts transformer; 52 layers (3 dense, 49 MoE), 256 experts with 8 selected per token; gated GQA and sliding-window attentionNot published

Full datasheets, every price and sourceBeam 1.0 501B A23B ↗Claude Sonnet 5.5 ↗

Anticipating threats and planning ahead. Collect coins while avoiding ghosts. Ghosts move before the player each turn, and collisions cost a life. 3 levels in sequence, up to 66 turns in total. Earlier moves and outcomes carry forward, testing learning across levels.

Beam 1.0 501B A23B 49.4/100Rank 18/47

Survived 1 of 3
Foresight: complete playing field
Level 39 ptsTurn 20 / 20

Claude Sonnet 5.5 59.6/100Rank 11/47

Survived 2 of 3
Foresight: complete playing field
Level 310 ptsTurn 20 / 20

Points per level

LevelBeam 1.0 501B A23BClaude Sonnet 5.5
Level 1Second Thoughts
18 ptsOut of lives
25 ptsSurvived
Level 2Pressure Pot
9 ptsOut of lives
10 ptsOut of lives
Level 3Hide or Flight
9 ptsSurvived
10 ptsSurvived

Cooperative planning and learning from experience. Coordinate two robots to push numbered cores onto matching sockets. Pressure plates hold doors open; moving either robot uses one turn. 5 levels in sequence, up to 152 turns in total. Earlier moves and outcomes carry forward, testing learning across levels.

Beam 1.0 501B A23B 37.3/100Rank 29/48

Cleared 2 of 5
Latch: complete playing field
Level 55 ptsTurn 30 / 40

Claude Sonnet 5.5 83.9/100Rank 4/48

Cleared 5 of 5
Latch: complete playing field
Level 520.6 ptsTurn 27 / 40

Points per level

LevelBeam 1.0 501B A23BClaude Sonnet 5.5
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
9.6 ptsCleared
10 ptsClearedFinished early · 1 beacon left
Level 3Relay vault
11.2 ptsFinished early
19.2 ptsCleared
Level 4Passing bay
3.6 ptsFinished early
18.2 ptsClearedFinished early · 3 beacons left
Level 5Second thoughts
5 ptsFinished early
20.6 ptsCleared

Newton's Mirror

Same task instructions

Physics, perspective and recursive reflections, tested together. Explore the test ↗

The judgment

Beam 1.0 501B A23B

Central object placement is fairly close, but the defining mirrored-room structure is missing. The paint colors suggest the required contact order without establishing their different interaction histories. The faint floor oval does not demonstrate valid reflection geometry, so it earns no reflection credit. Rounded volume and glossy paint provide limited material credit despite weak metallic finishes and oversized paint bodies.

Claude Sonnet 5.5

The near-field silhouettes, broad perspective and paint contact order are recognizable. Missing outer chains, truncated repetitions and absent ordered imagery within the main and reflected spheres substantially limit the reflection system. Sparse spherical highlights leave much of the curved room and emitter mapping unsupported, despite some plausible planar light sequences.

Score breakdown

CategoryBeam 1.0 501B A23BClaude Sonnet 5.5
State at 600 ms20.5/2524.0/25
Camera and placement11.5/1515.0/15
Reflections2.0/12035.0/120
Materials and scale3.0/1010.0/10
Floor-damage reward0.0/100.0/10

Benchmark task

A spinning metal sphere and paint in a mirrored room test physical reasoning, perspective and consistency across repeated reflections.

Selfie

Different task instructions

Visual construction and creative interpretation.

The judgment

Beam 1.0 501B A23B

An appealing expression and warm palette support a coherent simple cartoon. The central polishing joke is not legible: the cloth is unresolved and the nose sits away from the fan. Pointed radial plates, uncertain limb attachments and weak ground contact limit construction, while restrained surface detail limits material richness.

Claude Sonnet 5.5

The centered coral squid has a friendly, composed expression and a balanced flower-like silhouette. Eight thick arms and two slender tentacles remain visibly connected, with no inverted parts. The mantle is elongated rather than compact, and the arm spacing is uneven. Soft shading gives volume, but dense stippling weakens the requested smooth matte finish; the broad background halo makes depth less precise.

Score breakdown

CategoryBeam 1.0 501B A23BClaude Sonnet 5.5
Task & likeness4.0/108.0/10
Anatomy & construction3.5/108.0/10
Space & placement5.5/108.0/10
Light & reflections5.5/107.5/10
Purposeful detail4.5/108.0/10
Artistry & character4.0/108.0/10
Materials & effects4.5/108.0/10
Visual integrity7.0/108.5/10

Benchmark task

Beam 1.0 501B A23B

A golden pangolin polishes its oversized amber tail while its nose smudges the same scale. The scene tests expressive anatomy, physical contact and contrasting translucent, polished and soft materials.

Claude Sonnet 5.5

A coral squid with spreading arms tests connected anatomy, balanced composition and soft surface shading.

Mona Lisa

Different task instructions

Precise visual recall and portrait reconstruction.

The judgment

Beam 1.0 501B A23B

The candidate shows a faint warm oval against an almost entirely black field. Minimal placement and smooth tonal variation are visible, but the portrait, anatomy, crossed hands and landscape remain unreadable. The saved comparisons provide no specific evidence supporting a change to the baseline categories.

Claude Sonnet 5.5

The crossed hands, dark dress, restrained smile and winding landscape clearly recall the Mona Lisa. Replication is limited by the frontal symmetry, wide eyes, elongated neck and flattened fingers. Soft facial shading provides volume, but heavy darkness and pervasive crackle obscure forms. The composition is coherent; the landscape and fabric remain visibly schematic.

Score breakdown

CategoryBeam 1.0 501B A23BClaude Sonnet 5.5
Task & likeness0.0/106.5/10
Anatomy & construction0.0/105.0/10
Space & placement0.0/106.0/10
Light & reflections0.5/106.5/10
Purposeful detail0.0/106.0/10
Artistry & character0.0/106.5/10
Materials & effects0.0/106.0/10
Visual integrity0.0/106.5/10

Benchmark task

An SVG interpretation of the Mona Lisa tests facial likeness, anatomy and the composition of a familiar portrait.

Beach

Different task instructions

Creativity, perspective and visual beauty.

The judgment

Beam 1.0 501B A23B

A coherent, cheerful beach illustration fulfills the main subjects with clean shapes and a strong sunset focal point. Its basic geometric construction, ambiguous animal anatomy, shallow depth and schematic lighting limit its accomplishment. Decorative details provide interest without developing intricate forms or convincing physical surfaces.

Claude Sonnet 5.5

A richly designed beach illustration combines radiant sunset bands, intricate palm fans and playful silhouettes within a cohesive purple, coral and turquoise palette. Carefully varied accessories reward close inspection, while overlapping foreground forms and shoreline layers organize the abundant activity. Dense palm strokes compete with focal subjects; animal anatomy, relative scales and reflected silhouettes remain simplified.

Score breakdown

CategoryBeam 1.0 501B A23BClaude Sonnet 5.5
Task & likeness7.0/109.0/10
Anatomy & construction5.0/108.0/10
Space & placement6.0/108.5/10
Light & reflections5.0/108.5/10
Purposeful detail5.5/109.5/10
Artistry & character4.0/109.5/10
Materials & effects5.0/108.5/10
Visual integrity5.0/108.0/10

Benchmark task

A busy shoreline at sunset tests scene composition, animal forms and the relationship between light and water reflections.

Ground Truth

Different task instructions

Physical reasoning, light and visual reconstruction.

The judgment

Beam 1.0 501B A23B

This benchmark has not been assessed yet.

Claude Sonnet 5.5

This benchmark has not been assessed yet.

Benchmark task

A plank, computer mouse and blueberry in a steel room test physical stability, spatial relationships, materials and lighting.

Raccoon

Different task instructions

Scene composition and interacting subjects.

The judgment

Beam 1.0 501B A23B

A cheerful, readable illustration with recognizable animals, expressive faces and useful accessories. Simple rounded construction limits complexity, while ambiguous steering attachments and weak hull-to-water contact reduce physical coherence. Lighting and surface effects establish the setting without convincing environmental interaction.

Claude Sonnet 5.5

The raccoon clearly rides on the dog's back while the dog grips the jet ski controls. Expressive faces, vivid colors and a sweeping wake make the scene appealing. Visible limbs connect coherently, but overlapping steering paws and an indistinct control mounting weaken construction. Flat character lighting and simplified water limit depth and material realism.

Score breakdown

CategoryBeam 1.0 501B A23BClaude Sonnet 5.5
Task & likeness5.0/108.5/10
Anatomy & construction3.5/107.0/10
Space & placement5.5/108.0/10
Light & reflections4.0/106.5/10
Purposeful detail6.5/108.0/10
Artistry & character3.5/107.0/10
Materials & effects5.0/107.5/10
Visual integrity6.5/108.0/10

Benchmark task

A jet-ski scene pairs a canine driver with a raccoon passenger. It tests the placement and contact of interacting subjects, along with vehicle construction.

Pelican

Different task instructions

Subject construction and spatial relationships.

The judgment

Beam 1.0 501B A23B

A cheerful, clearly readable pelican-and-bicycle illustration with clean contours and balanced composition. Simple geometric construction limits artistic complexity, while ambiguous neck and steering overlaps, merged pedal contacts and an incomplete drivetrain weaken physical coherence.

Claude Sonnet 5.5

The pelican is immediately recognizable, with an expressive face, generous bill and appealing cycling pose. Spokes, chain, feathers and scarf provide purposeful detail. The bicycle largely holds together, though overlapping angular legs obscure the far foot’s pedal contact. Clean outlines and balanced composition succeed; flat surfaces and limited directional lighting constrain depth.

Score breakdown

CategoryBeam 1.0 501B A23BClaude Sonnet 5.5
Task & likeness5.5/109.0/10
Anatomy & construction4.5/107.5/10
Space & placement5.0/107.5/10
Light & reflections4.0/106.5/10
Purposeful detail4.0/108.0/10
Artistry & character4.0/107.5/10
Materials & effects4.0/106.5/10
Visual integrity5.5/108.0/10

Benchmark task

A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.